On Fri, May 10, 2024 at 11:25:09AM +0300, Laurent Pinchart wrote:
> Hi Hans,
>
> Thank you for the patch.
>
> On Fri, May 10, 2024 at 09:11:46AM +0200, Hans Verkuil wrote:
> > This reverts commit 9801b5b28c6929139d6fceeee8d739cc67bb2739.
> >
> > This patch introduced a potential deadlock scenario:
> >
> > [Wed May 8 10:02:06 2024] Possible unsafe locking scenario:
> >
> > [Wed May 8 10:02:06 2024] CPU0 CPU1
> > [Wed May 8 10:02:06 2024] ---- ----
> > [Wed May 8 10:02:06 2024] lock(vivid_ctrls:1620:(hdl_vid_cap)->_lock);
> > [Wed May 8 10:02:06 2024] lock(vivid_ctrls:1608:(hdl_user_vid)->_lock);
> > [Wed May 8 10:02:06 2024] lock(vivid_ctrls:1620:(hdl_vid_cap)->_lock);
> > [Wed May 8 10:02:06 2024] lock(vivid_ctrls:1608:(hdl_user_vid)->_lock);
> >
> > For now just revert.
> >
> > Fixes: 9801b5b28c69 ("media: v4l2-ctrls: show all owned controls in log_status")
> > Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
There should be a
Cc: stable@xxxxxxxxxxxxxxx
too, as this should be backported to v6.9.x.
> > ---
> > drivers/media/v4l2-core/v4l2-ctrls-core.c | 18 +++++-------------
> > 1 file changed, 5 insertions(+), 13 deletions(-)
> >
> > diff --git a/drivers/media/v4l2-core/v4l2-ctrls-core.c b/drivers/media/v4l2-core/v4l2-ctrls-core.c
> > index c59dd691f79f6..eeab6a5eb7bac 100644
> > --- a/drivers/media/v4l2-core/v4l2-ctrls-core.c
> > +++ b/drivers/media/v4l2-core/v4l2-ctrls-core.c
> > @@ -2507,8 +2507,7 @@ int v4l2_ctrl_handler_setup(struct v4l2_ctrl_handler *hdl)
> > EXPORT_SYMBOL(v4l2_ctrl_handler_setup);
> >
> > /* Log the control name and value */
> > -static void log_ctrl(const struct v4l2_ctrl_handler *hdl,
> > - struct v4l2_ctrl *ctrl,
> > +static void log_ctrl(const struct v4l2_ctrl *ctrl,
> > const char *prefix, const char *colon)
> > {
> > if (ctrl->flags & (V4L2_CTRL_FLAG_DISABLED | V4L2_CTRL_FLAG_WRITE_ONLY))
> > @@ -2518,11 +2517,7 @@ static void log_ctrl(const struct v4l2_ctrl_handler *hdl,
> >
> > pr_info("%s%s%s: ", prefix, colon, ctrl->name);
> >
> > - if (ctrl->handler != hdl)
> > - v4l2_ctrl_lock(ctrl);
> > ctrl->type_ops->log(ctrl);
> > - if (ctrl->handler != hdl)
> > - v4l2_ctrl_unlock(ctrl);
> >
> > if (ctrl->flags & (V4L2_CTRL_FLAG_INACTIVE |
> > V4L2_CTRL_FLAG_GRABBED |
> > @@ -2541,7 +2536,7 @@ static void log_ctrl(const struct v4l2_ctrl_handler *hdl,
> > void v4l2_ctrl_handler_log_status(struct v4l2_ctrl_handler *hdl,
> > const char *prefix)
> > {
> > - struct v4l2_ctrl_ref *ref;
> > + struct v4l2_ctrl *ctrl;
> > const char *colon = "";
> > int len;
> >
> > @@ -2553,12 +2548,9 @@ void v4l2_ctrl_handler_log_status(struct v4l2_ctrl_handler *hdl,
> > if (len && prefix[len - 1] != ' ')
> > colon = ": ";
> > mutex_lock(hdl->lock);
> > - list_for_each_entry(ref, &hdl->ctrl_refs, node) {
> > - if (ref->from_other_dev ||
> > - (ref->ctrl->flags & V4L2_CTRL_FLAG_DISABLED))
> > - continue;
> > - log_ctrl(hdl, ref->ctrl, prefix, colon);
> > - }
> > + list_for_each_entry(ctrl, &hdl->ctrls, node)
> > + if (!(ctrl->flags & V4L2_CTRL_FLAG_DISABLED))
> > + log_ctrl(ctrl, prefix, colon);
> > mutex_unlock(hdl->lock);
> > }
> > EXPORT_SYMBOL(v4l2_ctrl_handler_log_status);
--
Regards,
Laurent Pinchart
